eyewitness up on the stand. >> their desire to get high again trumped the lives and futures of four kids. unbelievable. she got everything she deserved. i was glad to be a part of it. up next, tragedy at a texas college. >> she's cold. >> she's cold to the touch? >> yes, ma'am. >> oh my god. >> it's very unusual for a 20-year-old girl to die suddenly of natural causes. >> tiny drops of blood could mean an accident. or a murder. >> we had no idea what had caused her death. >> there were just more questions than answers. >> eyewitnesses place a man at the scene. but are their descriptions accurate? >> had us really scratching our heads.

>> bryan, texas, is a college town that lies in the shadow of texas a&m. it's home to blinn college where jenna verhaalen and spencer hood were inseparable. >> jenna's parents say that he was just the love of her life, that they had dated for several years, went to prom together in high school. jenna just absolutely adored spencer. >> jenna and spencer planned to pursue careers in either law or government. and they lived in separate apartments at the same complex. >> the autumn woods apartment complex is right next to blinn college so there's quite a few students that live there. it's easy for them, close, easy access to the college. >> april 9th, 2008, after attending his morning classes, spencer stopped by jenna's apartment to pick up a book he'd left there. >> spencer arrived at jenna's apartment, he found the door unlocked and he went inside.

>> spencer found jenna's lifeless body on the bedroom floor. and asked a neighbor to call 911. >> she's just laying on the ground. she's not breathing. >> okay. can you touch her and see if she's warm to the touch? >> can you touch her, see if she's warm to the touch? she's cold. >> she's cold to the touch? >> yes, ma'am. >> oh my god. >> police and paramedics pronounce jenna dead at the scene. >> the only injuries that we could find on her were a small bruise on her forehead. she had also clenched down on her tongue with her feet. >> didn't appear to be any kind of robbery. her purse was hanging on a hook right next to the door. credit cards were there in her purse, there was cash in her purse, her keys were in the purse. >> there were no pills, no alcohol, no indications that she had committed suicide. >> spencer told police he last saw jenna the night before around midnight.

>> the two of them studied and then he left and went to his apartment. at 12:30 that morning. and then made a phone call to jenna a few minutes later to tell her good night. >> phone records showed that he had placed a call at 12:47 a.m. >> we know that she was discovered about 11:30 the next morning. so we've got less than a 12-hour window when jenna was killed. >> during the autopsy, the medical examiner found no evidence that jenna had been sexually assaulted. but he couldn't rule it out either. >> it has been my experience in some 30 years of performing autopsy examinations that the lack of genital injuries does not rule out a sexual assault. >> but he did find small, broken blood vessels in the whites of jenna's eyes, known as petechial hemorrhages. >> they're in that constellation of findings that we refer to as

stigmata of asphyxiation. tells me i need to look for a cause of asphyxiation. >> and he found it. jenna's larynx had been crushed. the conclusion was inescapable. >> this is a strangulation, and in great probability, manual strangulation by hands. >> a background check revealed that over the years, spencer and jenna had broken up several times, dated others, but always made up and got back together. >> knowing there were no signs of forced entry, i think you meet think, this was some kind of lovers' quarrel gone bad. >> we did ask spencer if he had killed jenna, and his response was "absolutely no." >> but would the forensic evidence support his claim?

as investigators looked into jenna verhaalen's background, they learned she was well liked and respected by her friends and classmates at blinn college in texas.

>> she didn't have any enemies, she didn't have fights with people, she didn't have arguments or disagreements. everybody had nothing but good things to say about her. >> jenna was a dedicated student who was working her way through school as a waitress at a local restaurant. >> she worked for everything that she had and didn't have -- i think a full-time job at wings and more while taking her classes. >> on the night of the murder jenna worked at the restaurant until 9:00 p.m. surveillance tapes revealed nothing suspicious. >> all we found was jenna just walking to her vehicle. we didn't find anybody following her. >> jenna returned to her apartment around 9:30. her boyfriend, spencer hood, said he stopped by and they spent about three hours studying together. and he left after midnight. then jenna's neighbors provided a possible lead. on the night of the murder, the neighbors were playing sand

volleyball in the courtyard in between the apartment buildings. around midnight, they saw a man walking from the direction of jenna's apartment. >> he was shirtless and he was acting very upset. we learned that this suspicious male had come out anywhere between the hours of midnight and 2:00 a.m. in fact, some of the girls that were playing said that he looked scary. >> witnesses said the man resembled 26-year-old sean stevens, also a college student who lived in an adjoining apartment building. according to friends, he'd once made a vulgar remark to jenna in the parking lot. >> it was more or less just some catcalls and stuff from sean's balcony down to the girls. and there were some words exchanged between jenna and sean. >> sean's apartment had a direct line of sight to jenna's apartment. we contacted him. sean was extremely nervous and was literally shaking.

>> sean denied any involvement in jenna's murder. he also said he wasn't the shirtless man walking from jenna's apartment on the night of her murder. >> but he couldn't provide accurate information about where he had been that night due to a large consumption of alcohol. >> then police uncovered a startling piece of information. two months before her murder, jenna told her family about an incident involving her apartment's maintenance man. it happened one morning after she got out of the shower. she found the maintenance man standing in her living room. >> he was there when he wasn't asked to be. and she didn't know that he was there. >> according to jenna, the man claimed he didn't hear the water running and believing the

apartment was empty, walked inside. >> it's creepy. it's creepy just to think about. you don't stick around while someone's in the shower, and then when they come out, leave. >> jenna became very upset and contacted the supervisor of the maintenance worker and explained to him what had happened. >> the worker's name was jeremy rosser. he was 29 years old, divorced, with two children. he had never been in trouble with the law. >> he comes from a religious background, his father's a pastor in a nearby town. >> but police were more than a little suspicious. so they conducted an experiment to see whether rosser's explanation had been truthful. >> when detectives fry and matthews go back to the apartment complex, they actually stand right at the front door and have someone go into jenna's bathroom, turn the shower on, close the door to the bathroom. they say from the front threshold of the door, you can clearly hear that the shower's running inside that apartment.

>> coincidentally, rosser was fired one week after jenna's murder. >> he had been terminated or fired because he wasn't coming to work anymore. >> police wanted to question rosser but he left town after he lost his job and no one knew where he was. they also discovered that jenna's boyfriend spencer hood was missing too. >> certainly our first area of focus was on spencer, as he was the last one to see her and the first one to find her. did not help his case any that he had suddenly left town. >> that left sean stevens, and he was nowhere to be found either. >> he's gone. he's not at school anymore, he's not at his apartment complex anymore. >> this made us a little bit suspicious. >> i started to realize, they just have no idea. they have no idea who did this. narrator: that whipped through the turbine which poured... surplus energy into the plant which generously lowered its price

and tipped off the house which used all that energy to stay warm through the storm. chipmunk: there's a bad storm comin! narrator: the internet of everything is changing how energy works. is your network ready?" ifyou may be muddlingble withrough allergies.nger... try zyrtec® for powerful allergy relief. and zyrtec® is different than claritin. because it starts working faster on the first day you take it. zyrtec®. muddle no more™.

time to celebrate ah, thwith your mates,mmer! grill a few dogs-- eh, hot dogs. bacon burgers... dachshund: "mattress discounters 4th of july sale ends soon"? bulldog: that cloud reminds me of...

radio announcer: the tempur-pedic cloud collection. bulldog: that's it! radio announcer: now with 48 months interest-free financing-- basset hound: free financing? radio announcer: or get a queen size serta pillow top on sale for just $597. bulldog: that's a ringer of a deal! radio announcer: mattress discounters 4th of july sale ends soon. ♪ mattress discounters police had three persons of interest in the murder of jenna verhaalen. her boyfriend, spencer hood. sean stevens, who matched the description of the man seen leaving jenna's apartment building the night of the murder. and jeremy rosser, a maintenance man at jenna's apartment complex who had once entered her apartment under suspicious circumstances. investigators hoped scientists

could find forensic evidence that would help narrow their search. first, scientists discovered skin cells under jenna's fingernails, which is not unusual when a victim is involved in a struggle. they extracted dna and discovered there were two genetic profiles, both male. >> one a minor contributor, one a major contributor. >> investigators also found a drop of blood on jenna's shirt collar and two drops of blood on the carpet near jenna's body. >> one of those did come back to be jenna's dna, and the other one came back to be the same unknown male contributor that was detected in the nail samples and on the neck of the shirt. >> she was fighting for her life. she is scratching him, scratching him deeply and hard enough that he's actively bleeding. >> this dna evidence was extremely exciting to us,

because we knew if we could ever get dna from a suspect that matched, we would have our killer. >> armed with the killer's dna, investigators wanted dna samples from jenna's boyfriend, spencer hood, her neighbor, sean stevens, and the maintenance man, jeremy rosser. mysteriously, all three left town after jenna's murder. while police searched for them, they also conducted a dna dragnet. they asked other men who lived in her apartment complex, as well as male co-workers, for dna samples. nearly 50 people willingly complied. but no one matched the dna from the crime scene. eventually, police found jenna's boyfriend, spencer hood, they hours away at his parents' home. >> i asked him the question, why he'd left town? what he'd explained was he was just upset. him and jenna were very close

and he wanted to be with his family. >> spencer was entirely cooperative. he allowed police to photograph him without his shirt, and police found no scratch marks on his body. he also answered questions without an attorney present and willingly provided a dna sample. next, police tracked down sean stevens at his parents' home 450 miles away in oklahoma. sean said he went home to see his brother, who was on leave from military service in iraq. when asked, sean willingly provided a dna sample without police having to resort to a court order. the only remaining suspect was jeremy rosser. police were finally able to locate him through his ex-wife, who provided an important clue. she said jeremy had shown signs of violence at the time of their divorce. >> they got in an argument, he

shoved her to the ground, and while she was on the ground he kneeled over her, put both hands around her neck. >> coincidentally, this incident occurred right around the time of jenna's murder. but for investigators, there was still one problem. >> a criminal check was done of rosser's background and we found no instances where he had been arrested in the past. this made him somewhat of an unlikely candidate for a crime of this type. >> when police questioned rosser he denied any involvement and was happy to cooperate. but in rosser's truck, investigators found a laptop computer. the serial number was traced to a tenant living in jenna's apartment complex who'd reported it stolen months earlier. they also found rosser still had keys to the apartments. >> this indicated to us that rosser had likely gone into many apartments during his term there as a maintenance worker. >> but jenna's apartment key was

not among those found in jeremy's possession. and just like the others, jeremy willingly provided a dna sample. >> my feelings of jeremy was that we might not have our person, being how cooperative he was and his demeanor. >> so investigators had three possibilities. would a dna match be among them? or was the killer still at large? huh...fifteen minutes could save you fifteen percent or more on car insurance. mmmhmmm...everybody knows that. well, did you know that old macdonald was a really bad speller? your word is...cow. cow. cow. c...o...w... ...e...i...e...i...o. [buzzer] dangnabbit. geico. fifteen minutes could save you...well, you know.

it's one of the fastest growing crimes in america. in fact, there's a new victim of identity theft every...three...seconds. so you have to ask yourself, am i next? one weak password could be all it takes. or trusting someone you shouldn't. over 100 million consumers had their personal information stolen in recent retail store and online security breaches. you think simply checking last month's credit score can stop identity thieves now? that alone just isn't enough.

but lifelock offers the most comprehensive identity theft protection available. as soon as the patented lifelock identity alert system detects a threat, you'll be notified by text, phone or email. ♪ your response helps stop thieves before they do damage to your identity... helping to keep you safe... with three powerful layers of protection. detecting threats to your finances, credit, and good name 24/7. alerting you to potential danger. and if anything is found, your resolution expert will help restore your identity. so you can get back to enjoying your life. ♪ lifelock watches out for you in ways banks and credit card companies alone just can't. plus, it's backed by a $1 million service guarantee. if your identity is ever compromised, lifelock will spend up to $1 million on experts to help restore it. try lifelock membership risk free for 60 days with promo code easy. that's 2 months of proactive protection to help keep your identity safe, risk free.

act now and get this multi-device charger. charge all your devices at once to save you time... a $30 value, free! call the number on your screen or go to lifelock.com/easy. try the most comprehensive identity theft protection available risk free for 60 days plus get a $30 multi-device charger, free. enrollment takes just minutes. your protection starts immediately. call the number on your screen or go to lifelock.com/easy. ♪

with dna samples from three suspects, scientists hope to determine who killed college student jenna verhaalen. and had it not been for science, there's no telling what would have happened. >> had we not had the dna under her nails or on the collar of her shirt or on the carpet, we may never have solved this crime. >> the dna results left no doubt. jeremy rosser was in jenna's apartment on the night of the murder. >> how would your skip cells be under her nails? >> i have no idea. >> you have no idea? >> handshake? i'm not sure but -- >> that wasn't a handshake. how would your blood end up on the collar of her shirt?

>> what snapped, what made him want to do this to her, is weird. >> when police arrested rosser, he wasn't surprised. >> did they inform you what the warrant was for? >> they wouldn't tell me. they said they'd tell me when i got up here. >> well, the warrant is for murder. >> there was no screaming, yelling, what are you talking about? that was a big indication. >> prosecutors believe that rosser's intrusion into jenna's apartment while she was in the shower was no accident. after that encounter,

prosecutors believe rosser used his master key again, on the night of the murder, to enter jenna's apartment while she was at work. this time, they believe he hid in jenna's second bedroom and waited for her. jenna came home around 9:30 p.m. but her boyfriend, spencer hood, also stopped by. something rosser probably didn't anticipate. this forced rosser to wait another three hours. >> i love you. >> i love you too. >> spencer left shortly after midnight. but he called jenna at 12:47 to say good night. after that call, jenna went to bed. and at some point, rosser

attacked. jenna fought for her life. scratching him, collecting his skin cells. he strangled her to death. tiny drops of rosser's blood landed on jenna's shirt and on the rug next to her body. >> i would like to say that jenna in her last moments, i guess, fought like she always fights. and she's been a fighter. and that was enough to help us identify who this person was so that we could try and achieve some small sense of justice for her and her family. >> when charged with jenna's murder, rosser admitted he was guilty, in order to spare his family the ordeals of a trial. rosser never revealed his motive. >> it's possible that jeremy entered jenna's apartment to

burglarize and it then once spencer left, jeremy may have exited the bedroom hoping to get whatever he was there to steal. and was caught by jenna. and then subsequently had to end up murdering her, being that she knew his identity. >> it's also possible the assault had something to do with his marital problems at the time. >> jenna looked very similar in build to rosser's ex-wife. he may have assaulted jenna based on the fact that he was angry with his ex-wife. >> the forensic evidence was crucial to this case. because we don't have a motive without his dna, we don't really have a motive for him going into that apartment. >> regardless of his motive, jeremy rosser was convicted of jenna verhaalen's murder and was sentenced to 55 years in prison. >> he has two children are going to grow up with a dad in prison. so -- there's a lot of people affected by the decisions that rosser made.

>> this case stands out to me, and i consider it to be one of the most important cases i've worked in my career, based on the type of person jenna was. she was a young person that had her life ahead of her. and it's just a tragic event that it has to happen to someone like her. up next. they meet in cyberspace. >> he was fishing for women on the internet. >> rebecca had sent suggestive pictures of herself. >> they made plans to meet face to face. >> they were getting all hot and heavy with each other. >> day later they were all dead. >> they all appeared to be execution-style murders. >> the killer disappears into thin air but not without a trace. >> every crime that happens these days probably has a digital component. >